Road grader blade support

ABSTRACT

A road grader blade support attachment including a frame, means for securing the frame to a vertically adjustable blade carrier on the grader, a tongue having a front end pivotally mounted on the frame to swing about a vertical axis, an axle carrying ground-engaging blade support wheels, and means mounting the axle for vertical adjustment on the trailing end of the tongue including a piston and cylinder device having a lower end connected to the axle and an upper end connected to the tongue.

United States Patent [191 Ryan [ 1 June 11, 1974 ROAD GRADER BLADE SUPPORT [75] Inventor: Kelly P. Ryan, Blair, Nebr.

[73] Assignee: Blair Manufacturing Co., Inc., Blair,

Nebr.

[22] Filed: Dec. 4, 1972 [2]] App]. No.: 311,850

[52] U.S. CI. 172/783, 172/763 [51] Int. Cl E02f 3/12 [58] Field of Search 172/783, 781, 413, 763,

[56] References Cited UNITED STATES PATENTS 1,968,412 7/1934 Lull 172/783 2,640,718 6/1953 Brown 172/763 3,191,324

6/1965 Beyers et a1. 172/783 1/1971 Stauber 172/783 2/1972 Eisenhardt 172/763 X Primary Examiner-Stephen C. Pellegrino Attorney, Agent, or FirmHofgren, Wegner, Allen, Stellman & McCord [57] ABSTRACT A road grader blade support attachment including a frame, means for securing the frame to a vertically adjustable blade carrier on the grader, a tongue having a front end pivotally mounted on the frame to swing about a vertical axis, an axle carrying ground-engaging blade support wheels, and means mounting the axle for vertical adjustment on the trailing end of the tongue including a piston and cylinderdevice having a lower end connected to the axle and an upper end connected to the tongue.

6 Claims, 6 Drawing Figures ROAD GRADER BLADE SUPPORT BACKGROUND OF THE INVENTION The present invention relates to means for supporting the ground-engaging blade in a motor-powered grader.

Generally speaking, a motor grader contacts the ground at three spaced positions in afront-to-rear direction, namely at the rear propulsion wheels, the front steering wheels, and the blade mounted intermediate the front and rear wheels. While the wheels are laterally spaced and afford some flexibility in adapting to variations in the road surface, the blade has a line contact with the ground and reacts to variations anywhere along the line of contact. As a result, when the speed of the grader increases and it encounters rough places in the road, the blade often develops a rythmic bounce or vibration which gouges a washboard pattern in the ground surface. The bounce and gouging are accentuated when the rear wheels encounter the washboard pattern gouged by the preceding blade. In order to prevent the undesirable washboard pattern, in the absence of other corrective measures, it is necessary for the operator to sharply reduce the speed of the grader, and sometimes the operation is carried on indefinitely in low speed gears.

In order to reduce the undesirable bounce and washboard gouging when the grader is operated at increased speeds, as described above, it has been proposed that the grader blade be separately supported by groundengaging wheels which enable the blade to work independently of the grader chassis. For example, US. Pat. No. 3,552,498 discloses a road grader blade mounting means including a resilient spring device which yieldably urges the blade toward the ground and also resiliently opposes movement toward the ground. The resilient means is used in conjunction with blade-supporting wheels which are vertically adjustable relative to the blade to provide a fine adjustment of the blade elevation. The shock-absorbing action of the resilient means and the fine adjustment afforded by the blade support wheels enables accurate positioning of the blade together with independent support for the blade which reduces objectionable bounce. As a result, better road surfaces are graded at higher speeds with less attention.

The prior US. Pat. No. 3,552,498 disclosed a blade support attachment for a road grader including a base or frame attachable to the blade carrier, a tongue pivotally mounted on the frame, an axle carrying blade support wheels, and means for vertically adjusting the axle relative to the tongue. It is desirable to provide a more compact attachment and one with improved adaptability facilitating use with various grader constructions.

SUMMARY OF THE PRESENT INVENTION It is a general object of the invention to provide an improved blade support attachment for a road grader.

A more specific object is to provide adjustable means adaptable for securing the attachment to blade carriers of various'constructions.

Another object is to provide an improved blade support attachment for a road grader including a compact arrangement of an upright piston and cylinder device together with appropriate guide means for vertically adjusting the blade support wheels relative to the frame structure which is attachable to the blade carrier.

In the preferred embodiment of the invention illustrated herein, the blade support attachment comprises a frame, means for securing the frame to a blade carrier in a grader, a tongue having a front end pivotally mounted on the frame to swing about a vertical axis, an axle assembly carrying ground-engaging blade support wheels, and a piston and cylinder device mounting the axle assembly for vertical adjustment on the trailing end of the tongue. The piston and cylinder device includes a first tubular guide of rectangular cross section disposed in an upright position around the cylinder and having a lower end secured to the tongue and an upper end secured to the cylinder, a second tubular guide of rectangular cross section disposed in the first guide and having a lower end secured to the axle assembly and connected to the piston rod, and guide strips secured on the outside of the second tubular guide engageable with the interior of the first tubular guide.

Preferably, the axle assembly is releasably secured to the piston and cylinder device so as to be readily removable when desired. To this end the axle assembly is held by clamping means including one clamp member on the second tubular guide and a separate clamp member releasably secured to the first clamp member.

As illustrated herein, the attachment frame is secured to the blade carrier by means including an upright suspension arm extending between the carrier and the rear of the frame. The front edge of the attachment frame is secured to the blade carrier by clamping means including a pair of clamp members, means for securing one clamp member to the frame, means for securing the clamp plates together in spaced positions gripping a portion of the blade carrier, and means for adjusting the spaced relationship of the blades to each other.

Preferably, the clamping means comprises a pair of similar clamp plates each having a transverse recess for gripping the blade carrier, bolts for securing one clamp plate to the frame, bolts for securing the clamp plates together in spaced positions embracing a portion of the blade carrier, and bolts in the other clamp plate for adjustably spacing the plates.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a substantial portion of a motor-powered road grader embodying the present invention;

FIG. 2 is a vertical longitudinal sectional view through resilient means connecting the blade support to the grader chassis;

FIG. 3 is an exploded perspective view illustrating the frame for the blade support attachment together with the means for attaching the frame to the blade carrier;

" F IG. 4 is an exploded perspective view illustrating the tongue of the blade support attachment together with the piston and cylinder connection of the tongue with the axle for the ground-engaging wheels.

FIG. 5 is a fragmentary side elevation of a tubular guide shown in FIG. 4; and

FIG. 6 is a bottom view of the guide member shown in FIG. 5.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT Referring now to the drawings in more detail, a road grader embodying the present invention, as illustrated in FIG. 1, includes a cab mounted on a chassis including a longitudinal frame member 12, rear propelling wheels 14, and front steering wheels 16. Behind the cab 10, not visible, there is an appropriate power unit for supplying propulsion drive to the rear wheels 14, under control of an operator in the cab 10. The front wheels are adapted to be steered by a steering mechanism indicated in general at 18 and including a steering wheel 20 accessible in the cab 10. The propulsion means and the steering mechanism form no part of the present invention and need not be described. in complete detail herein.

The chassis includes a front portion disposed between the steering wheels 16 for mounting a drawbar 22 extending rearwardly and supporting a circular carrier member 24 disposed beneath a central portion of the longitudinal frame member 12. The circular carrier 24 is formed with internal teeth as at 26 to facilitate angular adjustment on the drawbar 22 by means of suitable power driven mechanism including a gear box visible in part at 27.

In order to support a ground-engaging grader blade 28, the circular carrier 24 is formed at opposite sides with curved depending draft arms as at 30. Lower ends of the draft arms30 include apertures which support a transversely extending brace and pivot rod assembly as at 32. Angularly inclined braces 33 extend from a central portion on the circular carrier 24 outwardly respectively to the lower ends of the draft arms 30. To facilitate attachment of the blade 28 to the carrier in various adjusted positions, the back of the blade is formed with parallel longitudinally extending clamp ways as at 34 and 35. Each of the draft arms 30 carries a pivotal blade support 36 having'a lower end portion pivotally mounted at 37 on the lower end of the arm 30 and an upper portion in the shape of a quadrant 38 adapted to be secured to the arm 30 in angularly adjustedpositions. Each of the blade holders 36 is formed at the top and bottom with a clamp as at 40 engageable with the ways 34 and 35 on the back of the blade 28. It will be understood that the blade supports 36 are pivotally adjustable on the depending draft arms 30 so that the face of the blade 28 is angularly adjustable relative to the surface of the ground.

The blade 28 is laterally adjustable relative to the carrier 24 by a piston and cylinder device including a cylinder 44 secured to the depending draft arms 30 and a piston having a piston rod 46 secured to the blade as at 47. When the blade is loose in the clamp members 40, fluid may be admitted to the cylinder 44 for moving the blade laterally; v

The drawbar 22 is pivotally adjustable on the grader chassis so that the carrier 24 is movable vertically relative to the frame member 12 and relative to the ground. The rear end of the drawbar 22 is supported at opposite sides respectively by resilient suspension units 50 each having a lower end secured to the drawbar and an upper end secured to a laterally outwardly extending arm 51 pivotally mounted on the longitudinal frame member 12 to raise and lower the suspension unit 50.

As seen best in FIG. 2, each of the resilient suspension units includes a pair of concentric can-shaped members 52 and 54 secured to a plate 55 having an upper extension 56 with a ball joint connection 57 to the arm 51. The concentric members 52 and 54 are spaced and provide a housing for a coiled spring 59. The lower ends of the cans 52 and 54 are fitted telescopically on the outside of concentric can-shaped members 60 and 61 secured together at the lower end by a plate 62 having an extension 64 adapted to be secured to the drawbar 22. The lower outer can 61 is provided with an internal thread-shaped member as at 65 fitted between the coils of the spring 59 in a manner to function as an intermediate spring seat so that the single spring 59-functions both to resiliently urge the carrier 24 downwardly toward the ground and at the same time to resiliently oppose movement toward the ground. The lower end of the spring 59 is seated on an annular member 67 secured to the lower end of the upper inner can 52. The upper end of the spring is seated against closure member 55 connecting the upper ends of the cans 52 and 54.

In order to limit the downward movement of the carrier 24 relative to the frame member 12, if desired, the plate62 on the lower cans 60 and 61 is provided with a pair of upwardly extending rods as at 69 formed with spaced apertures as at 70 adapted to receive a pin as at 72 for securing a collar 73 on the rod 69 to engage a guide 74 on the outer upper can 54. In this way, it will be understood that while the carrier 24 is elevated, the collar may be adjusted downwardly on the rods 69 and locked by insertion of the pin 72 in the appropriate aperture 70 so that the downward movement of the blade is limited. Alternatively, the blade may even be held in elevated position.

In order to reduce vibration and bounce of the blade vertically relative to the grader chassis, a blade support attachment generally designated is secured to the blade carrier and includes ground-engaging wheels. The attachment 80 includes a generally horizontally disposed D-shaped frame plate 82 adapted to be secured to the blade carrier by means best illustrated in detail in FIG. 3. In general, the front edge of the frame plate 82 is secured to the crossbrace 32 by a pair of clamp means as illustrated at 84. Rear portions of the plate 82 are supported by means of adjustable suspension an'ns as at 86 each having an upper end pivotally connected to one of the inclined braces 33 and a lower end pivotally connected to the plate 82. In this manner, the plate is rigidly secured to the blade carrier and forms an extension thereof.

As best seen in FIG. 3, each of the clamp means 84 comprises a pair of similarly formed rectangularly shaped clamp plates 90 and 91 having inwardly facing recesses as at 92 adapted to receive the curved outer surface of the crossbrace 32 when the plates are clamped in place on the brace. One of the plates 90 and 91 is adapted to be securely fastened to the frame plate 82. As illustrated herein, the upper plate 90 is secured to the bottom surface of the frame 82 by means of a pair of bolts 94 and lock nuts 95. Intermediate the clamp plate 90 and the frame 82, there may be one or more spacers as at 96 provided for the purpose of variably spacing the plate 90 from the frame 82 in a manner to aid in fitting the attachment to existing graders with varying dimensions. The second clamp plate 91 is secured in spaced relation to the first clamp plate 90,

gripping the brace 32, by means of clamp bolts 98 adapted to receive lock nuts 99. In order to properly space the ends of the plates and 91 remote from the crossbrace 32, adjustable bolts are mounted in the clamp plate 91 so that the ends are engageable with the plate 90. It should be understood that the clamp means provides a flexible device which may be secured to the bottom of the frame 82, or inverted and secured to the top of the frame 82, while the clamp plates may be variably spaced from each other in order to fit crosspieces of various dimensions. It should also be understood that the clamp 84 may be installed with one of the plates 90 and 91 on one side of the frame 82 and the other plate on the other side of the frame 82.

As best illustrated in detail in FIG. 3, each of the upright suspension arms 86 includes an internally threaded sleeve 102 adapted to receive a threaded adjustable bolt 104 in a manner such that the sleeve and the bolt form an arm of adjustable length. In order to secure the upper end of the sleeve 102 to the angularly inclined brace 33, a clamp bracket 106 is formed with depending flanges 107 pivotally mounted on the sleeve member 102 by means of bolt 108. In this manner, the sleeve 102 may be substantially vertically disposed while the clamp bracket 106 may be angularly inclined. The bracket 106 is formed with a transverse recess as at 109 adapted to receive the periphery of the brace 33 and a clamp plate 110 is formed with a complementary recess 111. The plate 110 is secured to the bracket 106 by means of bolts as at 112 secured in place by nuts 113.

In order to attach the lower end of the bolt 104 to the frame 82, the lower end of the bolt is bifurcated to the frame 82, the lower end of the bolt is bifurcated at 115 and pivotally mounted on an upright flange of a circular head 116. The head 116 is adapted to rest on the frame 82 while captured by a clamp plate 118 having a central aperture 120 for the bolt 104 and a deformation 121 around the aperture for receiving the head 116. The plate 118 issecured to the frame 82 by means of bolts or screws as at 122. It will be understood that the lower end of the bolt 104 is rotatably and pivotally mounted relative to the frame 82.

Referring now to FIG. 4, in order to mount the ground-engaging wheels 83 for supporting the blade 28, a tongue is pivotally mounted on the front of the frame 82 and extends rearwardly. The front end of the tongue 130 is positioned beneath the frame plate 82 and above a spaced parallel bracket 132 secured beneath the plate 82. A pivot pin 134 is positioned in aligned apertures in the bracket 132, the tongue 130 and the plate 82. The pin is secured in frame 82 by means of a bolt 135 secured to a flange 136 on the bracket 132. The pin 134 is additionally retained against vertical displacement by means of a bolt 138 threadable into the upper end of the pin 134 and engageable with the top surface of the frame plate 82.

The rear end of the tongue 130 is formed with an upright tubular guide member 140 of rectangular crosssection having a lower end rigidly secured to the tongue. The upper end of the guide member 140 is closed and the'lower end is open to receive telescopically therein the upper portion of a tubular guide 142 of complementary cross-section having a lower end portion rigidly secured to a transversely extending clamp member 143 for an axle assembly including an axle 144. At opposite ends, the axle 144 carries rotatably mounted drums 146 for receiving the groundengaging wheels 83. In order to provide for vertical adjustment of the axle relative to the tongue, a cylinder 148 includes a rectangular head 149 at the upper end, and the cylinder is positionable in the guide member 140 so that the rectangular head 149 may be secured in the guide 140 as by means of bolts as at 150. The cylinder is thus rigidly secured in the guide member 140 and also closely surrounded by the inner guide member 142. The cylinder carries a reciprocable piston with a downwardly extending piston rod 152 having a lower end portion ,at 154 adapted to be pivotally secured in the lower guide member 142 by means of a pin 156 retained in place by a spring clip 157.

It will be understood that the mounting of the cylinder 148 in the upper guide member 140 and the connection of the piston rod 152 to the lower guide 142, and the mounting of the guide members 140 and 142 telescopically with respect to each other, provides for vertical reciprocable movement of the lower guide relative to the upper guide to raise and lower the wheels 83 relative to the tongue 130. As the wheels are lowered, the blade 28 is elevated. As the wheels are raised, the blade 28 is lowered In order to facilitate reciprocation of the guide 142 in the guide 140, guide 142 has guide strips secured on its outer surfaces, including on each of the front and rear surfaces a pair of laterally spaced vertically disposed bearing strips as at 158 welded or otherwise suitably secured on guide 142. On each of the laterally opposite surfaces, the guide 142 has a vertically disposed spacer strip as at 159, secured in place by welding for example. With the construction illustrated, the guide members 140 and 142 may be conveniently made from standard commercially available structural steel tubing. For example, both guides may be 1018 carbon steel, the outer member 140 being 6 x 6 x 3/8 inches and the inner member 142 being 4V2 x 4% x [/4 inches. The bearing strips 158 are preferably an aluminum bronze alloy bearing material. The spacer strips 159 may be steel.

The tubular guide 140 engages the bearing strips on the guide 142 over an extended length in a manner to enable vertical movement of the axle 144 relative to the tongue even though the guide 142 is offset from the axis of the axle 144. The rectangular cross section of the guides 140 and 142 prevents pivotal movement of the axle 144 relative to the tongue 130 about a vertical axis. The mounting of the guide 142 forwardly of the axle 144 enables a reduction in the over-all height of the blade support in contrast to an arrangement where the piston and cylinder device is aligned vertically over the axle 144. The arrangement illustrated also provides a compact over-all length in a front-to-rear direction, in contrast to arrangements where the axle 144 might be supported by a pivoted crank arm mounted on the tongue 130.

As the circular support 24 is angularly adjusted to vary the angle of the blade relative to the path of motion, the tongue 130 is free to swing about the vertical pivot pin 134 so that the wheels 83 trail properly. In order to facilitate angular adjustment of the tongue 130 relative to the frame plate 82, the tongue is formed at each side with a pair of angularly disposed brackets 160 adapted to receive a roller pin 162 carrying a bushing 163 for a bearing roller 164, adapted to engage the bottom surface of the D-shaped frame plate 82. The pivot 7 pin 162 is secured in place by a bolt 165 engageable with a depending flange 166 on the tongue 130.

In order to facilitate removal of the axle assembly carrying the ground-engaging blade support wheels 83, so that the wheels can be readily detached when they are not necessary, the axle assembly is releasably clamped to the clamp member 143 which is carried on the lower end of tubular guide 142. The clamp member 143 is an elongate recessed, half tubular member, and as best seen in FIGS. and 6, it is rigidly secured to the guide member 142 by means of a pair of bars 170 which are welded in the lower end of member 142 and project forwardly where they are welded to memer 143.

The axle assembly mounted in the clamp member 143 includes a tubular housing member 170 which carries an inner bushing 172 supporting the axle 144 for angular motion. At opposite ends, the axle 144 has oppositely offset portions 173 and 174 rotatably supporting wheel hubs 146, and the axle is normally biased to a position in which the offset portions 173 and 174 lie in a common horizontal plane by means of torsion spring means 176 in the housing 170 acting between the housing and the axle. In this manner the wheels are free to adjust vertically to local variations in the terrain without materially altering the position of the blade.

The housing member 170 is releasably clamped in the member 143 by a separate complementary clamp member 180 having a recessed central portion and flanges 181 along opposite edges adapted to be secured to similar flanges on clamp member 143 by bolts as at 183. Rotation of housing member 170 in the clamp members 143 and 180 is prevented by screws as at 183 which penetrate clamp member 180 and the housing member 170. The releasable clamp 180 may be easily removed so that the axle assembly and blade support wheels may be disconnected when the wheels are not necessary. When the wheels are desired,.the axle assembly may be readily attached by securing clamp member 180 in place.

I claim:

1. A road grader, comprising,

a. a chassis having propelling wheels and guiding wheels,

b. a drawbar pivotally mounted on the front of the chassis and extending rearwardly to swing vertically,

c. a circular carrier mounted on the drawbar for angular adjustment,

d. a horizontally disposed grader blade secured to the circular carrier to engage the ground,

e. resilient means on the chassis biasing the drawbar downwardly and resiliently supporting the drawbar,

f. a tongue having a front end pivotally mounted on the carrier to swing about a vertical axis,

g. an axle housing supporting an axle carrying ground-engaging blade support wheels,

h. a piston and cylinder device connected between the tongue and the axle housing for vertically adjusting the axle relative to the tongue including 1. a first tubular guide of rectangular cross section disposed in an upright position around the cylinder and secured to the tongue and the cylinder,

2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and secured to the axle housing and connected to the piston rod, and 3. wear strips of bearing material secured to the outer front and rear surfaces of the inner tubular guide engageable with the interior surfaces of the outer tubular guide.

2. A road grader, comprising,

a. a chassis having propelling wheels and guiding wheels,

b. a drawbar pivotally mounted on the front of the chassis and extending rearwardly to swing vertically,

c. a circular carrier mounted on the drawbar for angular adjustment,

(1. a horizontally disposed grader blade secured to the circular carrier to engage the ground,

e. resilient means on the chassis biasing the drawbar downwardly and resiliently supporting the drawbar,

f. a tongue having a front end pivotally mounted on the carrier to swing about a vertical axis,

g. an axle housing carrying an axle with ground- 2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and connected to the piston rod,

3. a first recessed clamp member on the lower end of the second tubular guide for receivingthe axle housing, I v V 4. a second recessed clamp member embracing the axle housing opposite the first clamp member, and

5. bolt means releasably securing the second clamp member to the first clamp member so that the axle is readily removable.

3. A road grader, comprising,

a. a chassis having propelling wheels and guiding wheels,

b. a drawbar pivotally mounted on the front of the chassis and extending rearwardly to swing verti-' cally,

c. a circular carrier mounted on the drawbar for angular adjustment,

d. a horizontally disposed grader blade secured to the circular carrier to engage the ground,

e. resilient means on the chassis biasing the drawbar downwardly and resiliently supporting the drawbar,

f. a tongue having a front end pivotally mounted on the carrier to swing about a vertical axis,

g. an axle housing supporting an axle carrying ground-engaging blade support wheels,

h. a piston and cylinder device connected between the tongue and the axle housing for vertically adjusting the axle relative to the tongue including 1. a first tubular guide of rectangular cross section disposed in an upright position around the cylinder and secured to the tongue and the cylinder,

2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and secured to the axle housing and connected to the piston rod,

3. wear strips of bearing material secured to the outer front and rear surfaces of the inner tubular guide engageable with the interior surfaces of the outer tubular guide, and

.clamp means for releasably securing the second tubular guide to the axle housing including a recessed clamp member fixed on the second tubular guide for receiving the axle housing and a separate recessed clamp member embracing the axle housing and releasably secured to the fixed clamp member.

4. A road grader, comprising,

a. a chassis having propelling wheels and guide wheels,

b. a drawbar pivotally 'mounted on the front of the chassis and extending rearwardly to swing vertically,

c. a circular carrier mounted on the drawbar for angular adjustment,

d. a pair of spaced draft arms extending downwardly from the carrier,

e. a cross brace connecting the lower ends of the draft arms,

f. inclined braces extending respectively from the carrier to the lower ends of the draft arms,

g. a horizontally disposed grader blade secured to the draft arms to engage the ground,

h. resilient means on the chassis biasing the drawbar downwardly and resiliently supporting the drawbar, and

i. a blade support attachment including 1. a D-shaped frame,

2. means for securing the frame to the rear of the blade and to the carrier in horizontal position with the curved portion of the D positioned rearwardly of the straight portion thereof,

3. a tongue having a front end mounted on the center of the straight portion of the frame to swing about a vertical axis,

4. an axle housing carrying an axle with groundengaging blade support wheels,

5. means mounting the axle housing for vertical adjustment on the trailing end of the tongue, and 6. a pair of upright suspension arms connected respectively between the inclined braces and rear portions of the frame.

5. A road grader as defined in claim 4, wherein the means mounting the axle housing for vertical adjustment on the trailing end of the tongue comprises a. a piston and cylinder device connected between the tongue and the axle housing for vertically adjusting the axle relative to the tongue including 1. a first tubular guide of rectangular cross section disposed in an upright position around the cylinder and secured to the tongue and the cylinder,

the tongue and the axle housing for vertically adjusting the axle housing relative to the tongue including l. a first tubular guide of rectangular cross section disposed in an upright position around the cylinder and secured to the tongue and the cylinder,

2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and pivotally connected to the piston rod, and

3. clamp means for releasably securing the second" tubular guide to the axle housing including a recessed clamp member fixed on the second tubular guide for receiving the axle housing and a separate recessed clamp member embracing the axle housing and releasably secured to the fixed clamp member. 

1. A road grader, comprising, a. a chassis having propelling wheels and guiding wheels, b. a drawbar pivotally mounted on the front of the chassis and extending rearwardly to swing vertically, c. a circular carrier mounted on the drawbar for angular adjustment, d. a horizontally disposed grader blade secured to the circular carrier to engage the ground, e. resilient means on the chassis biasing the drawbar downwardly and resiliently supporting the drawbar, f. a tongue having a front end pivotally mounted on the carrier to swing about a vertical axis, g. an axle housing supporting an axle carrying ground-engaging blade support wheels, h. a piston and cylinder device connected between the tongue and the axle housing for vertically adjuSting the axle relative to the tongue including
 1. a first tubular guide of rectangular cross section disposed in an upright position around the cylinder and secured to the tongue and the cylinder,
 2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and secured to the axle housing and connected to the piston rod, and
 3. wear strips of bearing material secured to the outer front and rear surfaces of the inner tubular guide engageable with the interior surfaces of the outer tubular guide.
 2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and secured to the axle housing and connected to the piston rod, and
 2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and pivotally connected to the piston rod, and
 2. A road grader, comprising, a. a chassis having propelling wheels and guiding wheels, b. a drawbar pivotally mounted on the front of the chassis and extending rearwardly to swing vertically, c. a circular carrier mounted on the drawbar for angular adjustment, d. a horizontally disposed grader blade secured to the circular carrier to engage the ground, e. resilient means on the chassis biasing the drawbar downwardly and resiliently supporting the drawbar, f. a tongue having a front end pivotally mounted on the carrier to swing about a vertical axis, g. an axle housing carrying an axle with ground-engaging blade support wheels, h. a piston and cylinder device connected between the tongue and the axle for vertically adjusting the axle relative to the tongue including
 2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and connected to the piston rod,
 2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and secured to the axle housing and pivotally connected to the piston rod, and
 2. means for securing the frame to the rear of the blade and to the carrier in horizontal position with the curved portion of the D positioned rearwardly of the straight portion thereof,
 2. a second tubular guide of rectangular cross section telescopically mounted relative to the first guide and secured to the axle housing and connected to the piston rod,
 3. A road grader, comprising, a. a chassis having propelling wheels and guiding wheels, b. a drawbar pivotally mounted on the front of the chassis and extending rearwardly to swing vertically, c. a circular carrier mounted on the drawbar for angular adjustment, d. a horizontally disposed grader blade secured to the circular carrier to engage the ground, e. resilient means on the chassis biasing the drawbar downwardly and resiliently supporting the drawbar, f. a tongue having a front end pivotally mounted on the carrier to swing about a vertical axis, g. an axle housing supporting an axle carrying ground-engaging blade support wheels, h. a piston and cylinder device connected between the tongue and the axle housing for vertically adjusting the axle relative to the tongue including
 3. a tongue having a front end mounted on the center of the straight portion of the frame to swing about a vertical axis,
 3. wear strips of bearing material secured to the outer front and rear surfaces of the inner tubular guide engageable with the interior surfaces of the outer tubular guide, and i. clamp means for releasably securing the second tubular guide to the axle housing including a recessed clamp member fixed on the second tubular guide for receiving the axle housing and a separate recessed clamp member embracing the axle housing and releasably secured to the fixed clamp member.
 3. clamp means for releasably securing the second tubular guide to the axle housing including a recessed clamp member fixed on the second tubular guide for receiving the axle housing and a separate recessed clamp member embracing the axle housing and releasably secured to the fixed clamp member.
 3. guide strips secured on the outside of the second tubular guide engageable with the interior of the first tubular guide.
 3. a first recessed clamp member on the lower end of the second tubular guide for receiving the axle housing,
 3. wear strips of bearing material secured to the outer front and rear surfaces of the inner tubular guide engageable with the interior surfaces of the outer tubular guide.
 4. a second recessed clamp member embracing the axle housing opposite the first clamp member, and
 4. A road grader, comprising, a. a chassis having propelling wheels and guide wheels, b. a drawbar pivotally mounted on the front of the chassis and extending rearwardly to swing vertically, c. a circular carrier mounted on the drawbar for angular adjustment, d. a pair of spaced draft arms extending downwardly from the carrier, e. a cross brace connecting the lower ends of the draft arms, f. inclined braces extending respectively from the carrier to the lower ends of the draft arms, g. a horizontally disposed grader blade secured to the draft arms to engage the ground, h. resilient means on the chassis biasing the drawbar downwardly and resiliently supporting the drawbar, and i. a blade support attachment including
 4. an axle housing carrying an axle with ground-engaging blade support wheels,
 5. means mounting the axle housing for vertical adjustment on the trailing end of the tongue, and
 5. A road grader as defined in claim 4, wherein the means mounting the axle housing for vertical adjustment on the trailing end of the tongue comprises a. a piston and cylinder device connected between the tongue and the axle housing for vertically adjusting the axle relative to the tongue including
 5. bolt means releasably securing the second clamp member to the first clamp member so that the axle is readily removable.
 6. A road grader as defined in claim 4, wherein the means mounting the axle housing for vertical adjustment on the trailing end of the tongue comprises a. a piston and cylinder device connected between the tongue and the axle housing for vertically adjusting the axle housing relative to the tongue including
 6. a pair of upright suspension arms connected respectively between the inclined braces and rear portions of the frame. 